Can you explain what you mean by "baby weight". Did you have a baby and you're trying to lose weight from a pregnancy?
How did you determine that you should weigh 180 lbs? Your weight is determined by your age and height.
You have to eat healthy meals/snacks and get plenty of exercise in order to lose weight. I'm not sure what the temptations are in school for eating. If there are a lot of vending machines with unhealthy snacks, either don't take extra money with you to buy them, or make sure you by-pass them on your way to/from classes.
If you live at home with your parents, ask them not buy snacks/drinks that are not healthy for you to have. Ask them to buy fruits and veggies to snack on, instead of candies, ice cream, sodas, etc. The very best thing you can do is make water your choice of drink.
If you participate in sports, that's a good way to get your exercise. If you don't, you'll have to find other ways to do it. Walking back and forth to school is a good way, if that's possible. If not possible, walking for 30 minutes/day in your neighborhood is the next best thing. Biking, swimming, dance, zumba or anything you like to do that keeps you moving for at least 30 minutes/day is good exercise.